Except for Geki Eiga (撃鋭牙), which suffers from obvious excessive red paint that requires another round of silver paint work to rectify, the entire paint work turned out to be very smooth, less stressful than I initially worried about. ^^

Excessive red paint on the shoulder armors is scratched away (very lightly and slowly) using a knife before the details are panel lined using Gundam Marker GM03 for Panel Lining Super Fine (Brown) again.

All done with the red details on these parts. ^^
Since they are extremely thin, the red ornaments on the rear skirt armor part aren't panel lined at all. I fear that extra lines added to them would thicken the details so much that the beauty to be seen in their delicate look would be distorted. ^^;

Excessive red paint on the front skirt armor is scratched away using a sharpened toothpick. The entire part is panel lined in the end.

The horns on the shoulder armors are painted using Tamiya Paint Marker X-11 Chrome Silver.

Excessive red paint around the curvy ornaments on Geki Eiga (撃鋭牙) is painted over using Gaia Metallic Color No. 121 Star Bright Silver. Excessive silver paint on the red details is then painted over using Gaia Color No. 003 Bright Red Gloss again. ^^;
I would probably go crazy if more rounds of such loop of annoyance are required on this one blade part. XD

All done for the blade parts.

The neck area is going to be painted to give it a separate look from the collar, but before that, the stripes beneath the chest are going to be painted first. ^^

(Left) Panel lines are added to identify the areas to be painted clearly.
(Right) The narrow valley is absolutely treacherous and would likely to cause serious paint spill if one isn't careful in painting said area. ^^;

Painted the parts using Gaia Metallic Color No. 122 Star Bright Gold.
The paint error on the back (see Part 3) has been completely covered up. ^^

The neck area mentioned earlier on is painted using Gaia Metallic Color No. 020 Gun Metal.

To give the model more additional details, the conductive pipes on either side of Koshin Gyan's face are painted with Gaia Metallic Color No. 020 Gun Metal. ^^

Test fitting the painted parts to see how the head would turn out when assembled. ^^

With the pipes painted, Koshin Gyan's face appears somewhat smaller than its default look, giving it a greater sense of sharpness and strength. It's certain a great outcome I didn't expect from that additional detail treatment. ^^

Anyway, all the parts will be kept in its box for a while before the final assembly. ^^